Monteith G R, Kable E P, Roufogalis B D
Department of Pharmacy, University of Sydney, NSW, Australia.
Clin Exp Hypertens. 1997 May;19(4):431-43. doi: 10.3109/10641969709084506.
Numerous studies investigating the possible role of altered Ca2+ homeostasis in hypertension have compared resting and agonist-stimulated intracellular free Ca2+ ([Ca2+]i) in cultured aortic smooth muscle cells from spontaneously hypertensive (SHR) and normotensive Wistar-Kyoto (WKY) rats. However, such studies have not given consistent results. Differences in the method used to load cells with the Ca(2+)-sensitive indicator fura-2 have been investigated here as a possible source of variability between studies. We also describe the adaptation of a fluorescence technique for the assessment of basal Ca2+ permeability in SHR and WKY through the measurement of Mn2+ influx. The results are consistent with the hypothesis that basal Ca2+ influx is elevated in cultured aortic smooth muscle cells from SHR compared to those from WKY. However, this was not reflected as a significant difference between the two strains in basal or angiotensin II (200 nmol/L)-stimulated [Ca2+]i. Furthermore, this result was not dependent on the protocol used to load cells with fura-2. Hence, measurement of bulk [Ca2+]i does not appear to be the most sensitive parameter for altered Ca2+ homeostasis in SHR. Other compartments of the cell may better reflect altered Ca2+ fluxes in hypertension and are discussed in this work.
众多研究探讨了钙稳态改变在高血压中可能发挥的作用，这些研究比较了自发性高血压大鼠（SHR）和正常血压的Wistar-Kyoto（WKY）大鼠培养的主动脉平滑肌细胞中静息状态和激动剂刺激后的细胞内游离钙浓度（[Ca2+]i）。然而，此类研究结果并不一致。本文研究了用于用钙敏感指示剂fura-2加载细胞的方法差异，这可能是研究之间变异性的一个来源。我们还描述了一种荧光技术的改进，通过测量锰离子内流来评估SHR和WKY的基础钙通透性。结果与以下假设一致：与WKY大鼠相比，SHR培养的主动脉平滑肌细胞基础钙内流升高。然而，这并未表现为两品系在基础或血管紧张素II（200 nmol/L）刺激的[Ca2+]i上的显著差异。此外，这一结果并不依赖于用于用fura-2加载细胞的方案。因此，测量总体[Ca2+]i似乎不是反映SHR钙稳态改变的最敏感参数。细胞的其他区室可能更能反映高血压中钙通量的改变，本文对此进行了讨论。
